g&g5e_tb_ch06

8/16/2019 G&G5e_TB_CH06

http://slidepdf.com/reader/full/gg5etbch06 1/10

Chapter 6—Proteins: Secondary, Tertiary, and Quaternary Structure

MULTIPLE CHOICE

1. Amino acid side chains capable of forming hydrogen bonds are usually located on the protein ____

and form hydrogen bonds primarily with the ____.a. surface, water solventb. interior, water solventc. surface, other amino acid side chains

d. interior, other amino acid side chainse. all are true

ANS: A PS: 1

!. ____ amino acids are almost never found in the interior of a protein, but the protein surface mayconsist of ____ amino acids.

a. Nonpolar, both polar and nonpolarb. Nonpolar, mostly nonpolarc. Polar, both polar and nonpolard. Polar, only polar

e. Polar, only nonpolar

ANS: " PS: 1

#. $lectrostatic interactions among amino acid residues on proteins may be damped out by highconcentrations of:a. water.

b. organic solvents.c. salts.d. heat.e. all of the above.

ANS: " PS: 1

%. An electrostatic interaction might occur within a protein between which of the following amino acidpairs at typical physiological p&'a. Ser(Asnb. Asp()lu

c. Arg("ysd. *ys(Asp

e. +al(le

ANS: - PS: 1

. ____ between tightly pac/ed amino acid side chains in the interior of the protein are a ma0or

contribution to protein structure.a. &ydrogen bonds

b. $lectrostatic interactionsc. "ovalent ester bondsd. +an der aals interactionse. All are true

ANS: - PS: 1

Garrett/Grisham 5e Test Bank 1

8/16/2019 G&G5e_TB_CH06


2. A hydrophobic interaction might occur within a protein between which of the following amino acidpairs'

a. Ser(leb. +al(*eu

c. yr("ysd. *ys(Asn

e. &is(+al

ANS: 3 PS: 1

4. All of the information necessary for folding the peptide chain into its 5native5 structure is contained in

the ____ of the peptide.a. amino acid se6uence

b. amino acid compositionc. configurationd. amino acid side chain chargese. all are true

ANS: A PS: 1

7. Amino acid se6uence is:a. primary structure.b. secondary structure.c. tertiary structure.

d. 6uaternary structure.e. regular structure.

ANS: A PS: 1

8. Secondary and higher orders of structure are determined by all $9"$P:a. hydrophobic interactions.

b. ionic bonds.c. van der aals forces.d. hydrogen bonds.

e. peptide bonds.

ANS: $ PS: 1

1. f an aspartic acid residue were present in the interior of a globular protein, it would most li/ely be _________.a. deprotonated and thus negatively chargedb. tightly associated with the ;<group of a lysine residue

c. react with a cysteine to form a thioesterd. react with a serine to form an estere. none of the above

ANS: 3 PS: 1

11. Planarity of the peptide bond means that no rotation occurs about the _____ bond while rotation is

allowed about the ____ and ____ bonds.a. "=>?<N@ "<"@ N<"b. "=>?<N@ "<"=>?@ N<"c. "<"=>?@ "=>?<N@ N<"d. N<"@ "<"=>?@ "=>?<Ne. none of the above


8/16/2019 G&G5e_TB_CH06


ANS: 3 PS: 1

1!. A ;amachandran plot shows:

a. the amino acid residues which have the greatest degree of rotational freedom.b. the sterically allowed rotational angles between ; groups and <carbons in a peptide.

c. the sterically allowed rotational angles between " and the amide nitrogen ="N? as well

as between " and the amide carbonyl carbon ="">?.

d. the sterically allowed rotational angles about the amide nitrogen =N&? and ">.

e. the amino acid residues that form <heli, <sheet, etc.

ANS: " PS: 1

1#. Alpha helices are stabiliBed primarily by:a. hydrogen bonds between the main chain peptide bond component atoms.

b. electrostatic interactions between ;<groups.c. hydrophobic interactions between the <carbons of the main chain.d. hydrogen bonding between the ;<groups.e. hydrophobic interactions between ;<groups and the solvent water.

ANS: A PS: 1

1%. n the ma0ority of <helies, each peptide carbonyl is hydrogen bonded to the peptide N& group ____ residues farther ____ the chain.

a. !, downb. %, up

c. #, downd. !, upe. %, down

ANS: 3 PS: 1

1. ____ and ____ act as heli brea/ers due to their uni6ue structure, which fies the value of the "N"

bond angle.

a. &istidine, lysineb. Proline, hydroyprolinec. Arginine, lysine

d. Serine, threoninee. yrosine, serine

ANS: 3 PS: 1

12. f the following section of a polypeptide is folded into an <heli, to which amino acid is the carbonylgroup of alanine hydrogen bonded'

ala<ser<val<asp<glu<leu<gly

a. serineb. aspartic acid

c. glutamic acidd. leucinee. valine

ANS: " PS: 1


8/16/2019 G&G5e_TB_CH06


14. hen the peptide =A$CC*AD$P? forms an <heli, which amino acid residue would be closest tobeing in the same position on the same face of the heli as is the initial alanine residue'a. C=#?b. A=2?

c. $=7?d. P=8?

e. *=?

ANS: " PS: 1

17. Antiparallel <sheets have:

a. sheets that progress from N to " termini in the same direction.b. usually all of their hydrophobic residues on one side of the sheet.c. all hydrophobic residues.d. all hydrophilic residues.

e. fibers that can be stretched or etended, but are not fleible.

ANS: 3 PS: 1

18. <urns in a peptide chain form a tight loop with hydrogen bonding of the carbonyl oygen with:a. side chain amine of lysine two amino acids down the chain.

b. amide proton on the net amino acid down the chain.c. amide proton of the glutamine side chain.d. amide proton of the residue three positions down the chain.e. amide proton of asparagine side chain.

ANS: - PS: 1

!. Polylysine is a random coil when the p& is less than 11, while it forms an <heli if the p& is raised to

greater than 1!. his is because at p& 1!:a. the lysine residues are negatively charged which electrostatically stabiliBes the heli.b. the positive charges on the lysine residues stabiliBes the <heli.c. the lysine residues are neutral which eliminates electrostatic repulsion between the ;

groups.d. the high concentration of >& ions in solution reduces the electrostatic repulsion between

the ;<groups.e. the lysine side chain changes configuration with p&.

ANS: " PS: 1

!1. he amino acid residue most li/ely to be found in a beta turn is:a. glycine.b. alanine.c. valine.

d. glutamic acid.e. leucine.

ANS: A PS: 1


8/16/2019 G&G5e_TB_CH06


!!. ____ <sheets characteristically distribute hydrophobic side chains on both sides of the sheet, and

____ <sheets are usually arranged with all their hydrophobic residues on one side of the sheet.a. Antiparallel, parallelb. Antiparallel, antiparallel

c. Parallel, antiparalleld. Parallel, parallele. None of the above

ANS: " PS: 1

!#. hich of the following amino acids would generally not be found in an <heli'

a. Alab. &isc. *eud. Ser

e. Det

ANS: - PS: 1

!%. ertiary structure is defined as:a. the se6uence of amino acids.

b. the folding of a single polypeptide chain in three<dimensional space.c. hydrogen bonding interactions between ad0acent amino acid residues into helical or

pleated segments.d. the way in which separate folded monomeric protein subunits associate to form oligomeric

proteins.

e. all are true.

ANS: 3 PS: 1

!. ertiary structure of proteins depends on all of the following $9"$P:a. protein structure depends on primary structure.b. <helices and <sheets often associate and pac/ close together.

c. secondary structures form whenever possible.d. proteins are stable as a single<layer structure.e. peptide segments between secondary structures are short.

ANS: - PS: 1

!2. he 5)ree/ Eey5 topology is composed of ____.

a. Ad0acent <helices oriented in the same directionb. Ad0acent <helices oriented in the opposite directionc. -iscreet regions of <sheet oriented in an antiparallel fashiond. -iscreet regions of <sheet oriented in an antiparallel fashione. Parallel <sheet structures connected by <helices

ANS: " PS: 1

!4. Cibrous proteins contain polypeptide chains ____ producing long fibers or large sheets.

a. with an abundance of aromatic amino acidsb. with an abundance of hydrophilic amino acidsc. organiBed approimately parallel along a single aisd. with amino acids arranged in a repeating =<a<b<c<d<?n se6uence

e. all are true


8/16/2019 G&G5e_TB_CH06


ANS: " PS: 1

!7. <Eeratin has all of the following characteristics $9"$P:a. primary component in hair, claws, fingernails, and horns of animals.

b. consists of four helical strands arranged as twisted pairs of two<stranded coiled coils.c. has associated hydrophobic strips on the two coiled coils.

d. presence of properly placed polar amino acids help to solubiliBe </eratin.e. has covalent disulfide bonds to stabiliBe the structure.

ANS: - PS: 1

!8. he 5permanent5 part of adding wave in hair is primarily due to:a. rearrangement of hydrogen bonds between hair fibers.b. reestablishment of new ionic interactions between hair fibers.c. brea/ing and reforming peptide bonds in the hair polypeptides.

d. rearrangement of hydrophobic interactions in hair fibers.e. reduction and re<oidation of disulfide bonds in hair fibers.

ANS: $ PS: 1

#. Sil/ fibers consist of ____ proteins consisting of alternating ____ and ____ or ____ residues.

a. fibroin@ glycine@ proline@ leucineb. </eratin@ alanine@ glycine@ serinec. fibroin@ glycine@ alanine@ threonined. </eratin@ cysteine@ alanine@ prolinee. fibroin@ glycine@ alanine@ serine

ANS: $ PS: 1

#1. "ollagen has the following characteristics $9"$P:a. ropocollagen is the basic structural unit.b. here is about ##F glycine in collagen.c. 3oth intermolecular and intramolecular crosslin/s help to stabiliBe the collagen fibrils.

d. Dodification of prolines occurs prior to collagen synthesis.e. netendable fibrous protein are components of connective tissues.

ANS: - PS: 1

#!. he uni6ue composition of collagen is accommodated in a structure called a=n?:a. <pleated sheet.

b. triple heli.c. heli<turn<heli motif.d. coiled coils.e. all are true.

ANS: 3 PS: 1

##. Prolyl hydroylase has all of the following characteristics $9"$P:a. re6uires citric acid.b. is activated by Ce!G.c. hydroylates proline residues in proteins.

d. re6uires molecular oygen.e. re6uires </etoglutarate.

ANS: A PS: 1


8/16/2019 G&G5e_TB_CH06


#%. A ma0or stabiliBing factor in the triple heli is a ____ structure such that ____ residues from the threestrands stac/ along the center of the triple heli.

a. linear, glub. linear, gly

c. staggered, lysd. staggered, gly

e. stac/ed, pro

ANS: - PS: 1

#. n hemoglobin, a ____ protein, the space between the helices is filled efficiently and tightly with

mostly ____ amino acid chains and with ____ side chains facing the outside of the protein structure.a. globular, hydrophobic, polar

b. globular, polar, nonpolarc. fibrous, hydrophobic, nonpolard. fibrous, polar, nonpolare. none are true

ANS: A PS: 1

#2. hy should the core of most globular and membrane proteins consist almost entirely of <heli and <

sheets'a. &ydrogen bonded structures must be /ept away from water solvent.b. &ighly polar N& and "H> moieties of the peptide bac/bone must be neutraliBed in the

hydrophobic core of the protein.c. &ydrogen bonding only occurs in the core of proteins.

d. rapped water stabiliBes the heli and sheet structures.e. None are true.

ANS: 3 PS: 1

#4. he outward face of a=n? ____ consists mainly of polar and charged residues, whereas the inner facecontains mostly nonpolar, hydrophobic residues.

a. <sheet

b. configurationc. <turnd. amphiphilic heli

e. all are true

ANS: - PS: 1

#7. A <barrel would most li/ely be composed of ____.a. parallel <sheets connected by regions of <helib. parallel <sheets connected by <turns.

c. parallel <sheets connected by regions of random coil.d. parallel <sheets connected disulfide bonds.

e. both a and c are correct.

ANS: $ PS: 1


8/16/2019 G&G5e_TB_CH06


#8. Cleible, disordered segments of proteins are commonly high in the amino acid:a. leu

b. lysc. ser

d. proe. asp

ANS: 3 PS: 1

%. hich of the following would be the most rapidly occurring event giving rise to protein motion'a. hinge<bending movement between protein domains

b. tyrosine ring flipc. cis-trans isomeriBation of proline

d. protein conformational changee. both b and c are e6ually rapid

ANS: 3 PS: 1

%1. hich statement is correct about the motif'a. he two <strands are antiparellel.b. he peptide segment connecting the <strands usually contains no more than five amino

acids.c. he peptide segment connecting the two <strands commonly contains proline.d. he cross<over connection itself contains an <helical segment.e. none are correct.

ANS: - PS: 1

%!. All are true about the tertiary structure of the enByme triose phosphate isomerase $9"$P:

a. ts <strands are parallel.b. ts <helices are in the interior of the molecular structure.

c. t contains a <barrel in the center of its structure.d. t is composed entirely of alternating <helices and <strands.

e. All are true.

ANS: 3 PS: 1

%#. All are classes of globular proteins according to type and arrangement of secondary structure

$9"$P:a. small metal< and disulfide<rich proteins.b. parallel or mied <sheet.c. antiparallel <sheet.

d. antiparallel <heli.e. all are true.

ANS: $ PS: 1

%%. ____ are eamples of antiparallel <heli proteins.a. riose phosphate isomeraseb. Pyruvate /inasec. Clavodoin

d. &emoglobine. Papain

ANS: - PS: 1


8/16/2019 G&G5e_TB_CH06


%. ____ is an eample of a disulfide<rich protein.a. nsulin

b. )lyceraldehyde<#<phosphate dehydrogenasec. &emoglobin

d. riose phosphate isomerasee. All are true.

ANS: A PS: 1

%2. ____ are proteins that help other proteins to fold.a. mmunoglobulins

b. Phospholipasesc. Synthetases

d. Dolecular chaperonese. Proteases

ANS: - PS: 1

%4. All are structural and functional advantages to 6uaternary structure $9"$P:a. cooperativity.

b. stability.c. bringing catalytic sites together.d. genetic economy and efficiency.e. all are true.

ANS: $ PS: 1

%7. All of the statements about the tertiary structure of the enByme triose phosphate isomerase are correct$9"$P:a. ts <strands are parallel.b. ts <helices are in the interior core of the molecular structure.c. t contains a <barrel in the center of its structure.d. t is composed entirely of alternating <helices and <strands.

e. &ydrophobic residues are buried between concentric layers.

ANS: 3 PS: 1

%8. Arrange the steps involved in folding of globular proteins into a proper se6uence.

A. 5Dolten globule5 formation of assembled domains.

3. Cormation of domains through cooperative aggregation of folding nuclei.". Ad0ustment in the conformation of domains.-. ;apid and reversible formation of local secondary structure.$. Cinal protein monomer formation.

a. A, 3, ", -, $

b. 3, ", $, A, -c. -, ", 3, A, $

d. -, 3, A, ", $e. 3, -, ", A, $

ANS: - PS: 1


8/16/2019 G&G5e_TB_CH06


. hich of the following does not contribute to the spontaneous nature of the protein folding process'a. formation of hydrogen bonds and electrostatic interactions

b. loss of translational freedom as portions of the protein interactc. formation of hydrophobic interactions

d. both a and c

ANS: 3 PS: 1

1. hich of the following proteins does not have 6uaternary structure'

a. immunoglobulinsb. insulin

c. glycogen phosphorylased. myoglobin

e. alcohol dehydrogenase

ANS: - PS: 1

!. hich of the following items was one of the crucial elements of the Anfinsen eperiment with

ribonuclease A'a. hydrophobic interactions were disrupted by the addition of <mercaptoethanolb. correct formation of disulfide bonds was achieved even with urea present

c. removal of <mercaptoethanol resulted in complete denaturation of the proteind. the presence of 7 cysteine residues means that there are 1 different disulfide bondpossibilities

e. none of the above

ANS: - PS: 1

#. n the tertiary structure of a protein, an electrostatic interaction could form between the ;<groups of

which two amino acids'a. )ln and *ysb. Asp and hrc. *eu and Asp

d. )lu and Arg

e. Arg and &is

ANS: - PS: 1

%. n the tertiary structure of a protein, a hydrophobic interaction could form between the ;<groups ofwhich two amino acids'

a. Ala and Serb. Asn and yr

c. *eu and +ald. +al and &ise. Pro and )ln

ANS: " PS: 1


g&g5e_tb_ch06

Documents